/*
 * Copyright (c) 2000, 2005, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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// SAX locator interface for document events.
// http://www.saxproject.org
// No warranty; no copyright -- use this as you will.
// $Id: Locator.java,v 1.2 2004/11/03 22:55:32 jsuttor Exp $

package org.xml.sax;


/**
 * Interface for associating a SAX event with a document location.
 *
 * <blockquote>
 * <em>This module, both source code and documentation, is in the
 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
 * for further information.
 * </blockquote>
 *
 * <p>If a SAX parser provides location information to the SAX
 * application, it does so by implementing this interface and then
 * passing an instance to the application using the content
 * handler's {@link org.xml.sax.ContentHandler#setDocumentLocator
 * setDocumentLocator} method.  The application can use the
 * object to obtain the location of any other SAX event
 * in the XML source document.</p>
 *
 * <p>Note that the results returned by the object will be valid only
 * during the scope of each callback method: the application
 * will receive unpredictable results if it attempts to use the
 * locator at any other time, or after parsing completes.</p>
 *
 * <p>SAX parsers are not required to supply a locator, but they are
 * very strongly encouraged to do so.  If the parser supplies a
 * locator, it must do so before reporting any other document events.
 * If no locator has been set by the time the application receives
 * the {@link org.xml.sax.ContentHandler#startDocument startDocument}
 * event, the application should assume that a locator is not
 * available.</p>
 *
 * @author David Megginson
 * @see org.xml.sax.ContentHandler#setDocumentLocator
 * @since SAX 1.0
 */
public interface Locator {


  /**
   * Return the public identifier for the current document event.
   *
   * <p>The return value is the public identifier of the document
   * entity or of the external parsed entity in which the markup
   * triggering the event appears.</p>
   *
   * @return A string containing the public identifier, or null if none is available.
   * @see #getSystemId
   */
  public abstract String getPublicId();


  /**
   * Return the system identifier for the current document event.
   *
   * <p>The return value is the system identifier of the document
   * entity or of the external parsed entity in which the markup
   * triggering the event appears.</p>
   *
   * <p>If the system identifier is a URL, the parser must resolve it
   * fully before passing it to the application.  For example, a file
   * name must always be provided as a <em>file:...</em> URL, and other
   * kinds of relative URI are also resolved against their bases.</p>
   *
   * @return A string containing the system identifier, or null if none is available.
   * @see #getPublicId
   */
  public abstract String getSystemId();


  /**
   * Return the line number where the current document event ends.
   * Lines are delimited by line ends, which are defined in
   * the XML specification.
   *
   * <p><strong>Warning:</strong> The return value from the method
   * is intended only as an approximation for the sake of diagnostics;
   * it is not intended to provide sufficient information
   * to edit the character content of the original XML document.
   * In some cases, these "line" numbers match what would be displayed
   * as columns, and in others they may not match the source text
   * due to internal entity expansion.  </p>
   *
   * <p>The return value is an approximation of the line number
   * in the document entity or external parsed entity where the
   * markup triggering the event appears.</p>
   *
   * <p>If possible, the SAX driver should provide the line position
   * of the first character after the text associated with the document
   * event.  The first line is line 1.</p>
   *
   * @return The line number, or -1 if none is available.
   * @see #getColumnNumber
   */
  public abstract int getLineNumber();


  /**
   * Return the column number where the current document event ends.
   * This is one-based number of Java <code>char</code> values since
   * the last line end.
   *
   * <p><strong>Warning:</strong> The return value from the method
   * is intended only as an approximation for the sake of diagnostics;
   * it is not intended to provide sufficient information
   * to edit the character content of the original XML document.
   * For example, when lines contain combining character sequences, wide
   * characters, surrogate pairs, or bi-directional text, the value may
   * not correspond to the column in a text editor's display. </p>
   *
   * <p>The return value is an approximation of the column number
   * in the document entity or external parsed entity where the
   * markup triggering the event appears.</p>
   *
   * <p>If possible, the SAX driver should provide the line position
   * of the first character after the text associated with the document
   * event.  The first column in each line is column 1.</p>
   *
   * @return The column number, or -1 if none is available.
   * @see #getLineNumber
   */
  public abstract int getColumnNumber();

}

// end of Locator.java
